One of the primary advantages to having a peer group at any age is the support that can be obtained from a social network. Having a group of friends means that you are less likely to be lonely, more likely to feel like you belong, have increased self-worth, and feel more secure, according to the Mayo Clinic article "Social support: Tap this tool to beat stress." If you have a peer group, you will think more positively about yourself because others value spending time with you. In addition, having friends gives you access to information, advice and guidance in all areas of life.

Peer pressure isn't always negative, suggests Brett Laursen, professor of psychology and Ph.D., in the American Psychological Association article, "Speaking of Psychology: The good and bad of peer pressure." If you have a group of friends who volunteer their time, have ambitious school- or work-related goals and positive relationships with family, then you are likely to hold the same values and beliefs. In addition, having high-quality friendships sets you up for success in the social world. The more positive your relationships are with your peer group, the more likely you are to have good relationships in the future.

There is, of course, a downside to the influence of a peer group. Although negative peer pressure is not enforced in the way many people think (peers don't usually "pressure" you to do anything; rather, you change your behavior because you want to fit in), it still exerts an influence. If you start hanging around with a bad crowd, their values and beliefs have the potential to negatively affect your behavior. Though negative peer influences can span a lifetime, we know that between the ages of 14 and 18 is when peer influence peaks -- and is also when you can best develop the skills to stand up for what you believe is right, according to the 2007 Temple University study "Age differences in resistance to peer influence" published in the journal Developmental Psychology. Those in this age group need to be particularly aware of potential influences and how to be prepared for them.

When you have a peer group, it is also possible to feel the sting of rejection. Though this is more common during childhood and adolescence, even adults may find themselves given the cold shoulder by a former circle of friends. If you haven't been rejected for a good reason (such as being overly aggressive or bossy), it's best not to take the situation personally. Often peer groups shift with time, and there isn't any reason why you can't strike up new friendships. Find a group with whom you share similar interests, values and goals, and you may find those positive influences leading to good changes in your life.